I think it's mostly a matter of personal style and preference and if it's for your own use you can pretty much do what you like.
Various arguments include:
Should code be mixed with mark-up at all? eg. MVC
What is the more efficient use of resources? i.e. memory and processing
and more I can't think of ATM
In this case, because it's WordPress a lot of the code will need to conform to WordPress standards to fit in, but there's still plenty of leeway.
IMHO as long as you can read it easily, it makes sense to you, and it works, then it's probably good enough.
You'll know when you need to change whatever approach you take when you start having problems. I find that as long as it's only a few it isn't a problem or likely to become one. But if it's a lot I prefer HEREDOC syntax instead.